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Mi Sook Seo

Publications and source records attributed to Mi Sook Seo.

15 recordsLinked to original sources
PubMed2007

Oxidative N-dealkylation reactions by oxoiron(IV) complexes of nonheme and heme ligands.

Nonheme and heme iron monooxygenases participate in oxidative N-dealkylation reactions in nature, and high-valent oxoiron(IV) species have been invoked as active oxidants that effect the oxygenation of organic substrates. The present study describes the first example of the oxidative N-dealkylation of N,N-dialkylamines by synthetic nonheme oxoiron(IV) complexes and the reactivity comparisons of nonheme and heme oxoiron(IV) complexes. Detailed mechanistic studies were performed with various N,N-dialkylaniline substrates such as para-substituted N,N-dimethylanilines, para-chloro-N-ethyl-N-methylaniline, para-chloro-N-cyclopropyl-N-isopropylaniline, and deuteriated N,N-dimethylanilines. The results of a linear free-energy correlation, inter- and intramolecular kinetic isotope effects, and product analysis studied with the mechanistic probes demonstrate that the oxidative N-dealkylation reactions by nonheme and heme oxoiron(IV) complexes occur via an electron transfer-proton transfer (ET-PT) mechanism.

Heme↗
PubMed2006

Identification of an "end-on" nickel-superoxo adduct, [Ni(tmc)(O2)]+.

An "end-on" Ni2+-superoxo adduct has been prepared via two independent synthetic routes and its structure ascertained by spectroscopic and computational methods. The new structure type in nickel coordination chemistry is supported by resonance Raman and EPR spectroscopic features, the former displaying a high frequency nu (O-O) mode (1131 cm-1) consistent with significant superoxo character. The Ni2+-superoxo adduct oxidizes PPh3 to OPPh3 in quantitative yield.

Heterocyclic Compounds↗
PubMed2006

Nonheme iron(II) complexes of macrocyclic ligands in the generation of oxoiron(IV) complexes and the catalytic epoxidation of olefins.

Mononuclear nonheme oxoiron(IV) complexes bearing 15-membered macrocyclic ligands were generated from the reactions of their corresponding iron(II) complexes and iodosylbenzene (PhIO) in CH(3)CN. The oxoiron(IV) species were characterized with various spectroscopic techniques such as UV-vis spectrophotometer, electron paramagnetic resonance, electrospray ionization mass spectrometer, and resonance Raman spectroscopy. The oxoiron(IV) complexes were inactive in olefin epoxidation. In contrast, when iron(II) or oxoiron(IV) complexes were combined with PhIO in the presence of olefins, high yields of epoxide products were obtained. These results indicate that in addition to the oxoiron(IV) species, there must be at least one more active oxidant (e.g., Fe(IV)-OIPh adduct or oxoiron(V) species) that effects the olefin epoxidation. We have also demonstrated that the ligand environment of iron catalysts is an important factor in controlling the catalytic activity as well as the product selectivity in the epoxidation of olefins by PhIO.

Alkenes↗
PubMed2006

[Knowledge and learning needs related to cancer treatment in gynecological cancer patients].

PURPOSE: This study was to investigate the knowledge and learning needs of chemotherapy in gynecological cancer patients. METHOD: The subjects consisted of 103 gynecological cancer patients receiving chemotherapy from April 2005 to August 2005. Data was collected using a questionnaire about knowledge and learning needs of chemotherapy. The data was analyzed by t-test, ANOVA, Scheffe test, and Pearson's correlation coefficient using SAS. RESULT: Average scores of knowledge and learning needs of general treatment and care were 2.74, and 3.30 respectively. Average score of knowledge and learning needs of chemotherapy were 2.54, and 3.23 respectively. Learning needs of general treatment and care and of chemotherapy were significantly different in relation to marital status, educational level, family support, the operation, and the amount of chemotherapy received. Items with the highest level of learning needs were the symptoms of recurring illness of general treatment, and minimizing side effects of chemotherapy. There were a negative correlation between knowledge and learning needs on general treatment and a positive correlation between knowledge and learning needs on chemotherapy but there were not significant statistically. CONCLUSION: The level of learning needs related to cancer treatment was high, whereas, that of knowledge was low. Therefore, when designing an educational program for gynecological cancer patients, understanding of learning needs is necessary. Also, consideration of a patient's characteristics, and a systematic and detailed educational program should be provided.

Adult↗
PubMed2005

Axial ligand substituted nonheme FeIV=O complexes: observation of near-UV LMCT bands and Fe=O Raman vibrations.

Axial ligand substitution of a mononuclear nonheme oxoiron(IV) complex, [FeIV(O)(TMC)(NCCH3)]2+ (1) (TMC = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane), leads to the formation of new FeIV=O species with relatively intense electronic absorption features in the near-UV region. The presence of these near-UV features allowed us to make the first observation of Fe=O vibrations of S = 1 mononuclear nonheme oxoiron(IV) complexes by resonance Raman spectroscopy. We have also demonstrated that the reactivity of nonheme oxoiron(IV) intermediates is markedly influenced by the axial ligands.

Iron↗
PubMed2005

Mononuclear nonheme ferric-peroxo complex in aldehyde deformylation.

A mononuclear nonheme ferric-peroxo complex bearing a macrocyclic tetradentate N4 ligand, [(TMC)Fe(III)-O2]+, was prepared and used in mechanistic studies of aldehyde deformylation; a catalytic aldehyde deformylation by a nonheme iron(II) complex, [Fe(II)(TMC)]2+, and molecular oxygen is reported as well.

Aldehydes↗
PubMed2005

A highly selective fluorescent chemosensor for Pb2+.

A new fluorescent sensor based on rhodamine B for Pb2+ was synthesized. The new fluorescent sensor showed an extreme selectivity for Pb2+ over other metal ions examined in acetonitrile. Upon the addition of Pb2+, an overall emission change of 100-fold was observed, and the selectivity was calculated to be 200 times that of Zn2+. The signal transduction occurs via of reversible CHEF (chelation-enhanced fluorescence) with this inherent quenching metal ion.

Journal Article↗
PubMed2005

Dioxygen activation and catalytic aerobic oxidation by a mononuclear nonheme iron(II) complex.

We have used dioxygen, not artificial oxidants such as peracids, iodosylarenes, and hydroperoxides, in the generation of a mononuclear nonheme oxoiron(IV) complex, [Fe(IV)(TMC)(O)]2+ (TMC = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane), from its corresponding Fe(II) complex, [Fe(TMC)(CF3SO3)2]. The formation of oxoiron(IV) species by activating dioxygen was markedly dependent on iron(II) complexes and solvents, and this observation was interpreted with the electronic effect of iron(II) complexes on dioxygen activation to form oxoiron(IV) species. A catalytic aerobic oxidation of organic substrates was demonstrated in the presence of the [Fe(TMC)]2+ complex. By carrying out 18O-labeled water experiment, we were able to conclude that the oxidation of organic substrates was mediated by an oxoiron(IV) intermediate, not by a radical type of autoxidation process.

Aerobiosis↗